Micro-electro-mechanical-systems (MEMS) technology has shown tremendous growth in recent years. Significant advances have also been made in the fabrication of MEMS devices for application in RF and microwave frequencies. Switching circuits utilizing this technology have been extensively studied since they are an important component in many RF and wireless systems. RF MEMS switches have already shown superior electrical performance to solid state p-i-n and FET switches at high frequencies. Due to these qualities, as well as their small size and their manufacturability using well characterized semiconductor processing techniques, RF MEMS switches have the potential to be a viable replacement to their solid state switch counterparts.
However, p-i-n diode and FET switches still outperform MEMS switches in switching speed and actuation voltage level. Solid state switches can switch between states in nanoseconds with very low voltage levels; generally at TTL levels. The fastest MEMS switches have so far been demonstrated with switching speeds in the microsecond range or the sub microsecond range.
Additionally, in the last few years, there has been an increase in the use of focused ion beam (FIB) milling for micro and nano structure fabrication. The increase is mainly due to the FIB's ability to mill material with high precision, yielding high-aspect-ratio structures with relatively smooth sidewalls without the use of a mask. Devices such as microfabricated accelerometers, BSCCO stacked junctions, microgratings for integrated optics, and micromilled trenches have already been demonstrated. FIB milled capacitors for micro- and millimeter wave application are also known in the art.
Accordingly, what is needed in the art is an improved MEMS switch having a lower actuation voltage and a faster switching speed in a small form factor.